feat: 联网搜索支持按时间范围过滤

- OnlineSearch 方法新增 daysAgo 参数，支持按最近天数筛选搜索结果
- 百度搜索请求增加 search_filter 时间范围（gte/lte）
- 补充相关模型与 JSON 源生成配置
- 更新工具描述，明确近期与实时信息范围

Yi.Abp.Net8/module/ai-hub/Yi.Framework.AiHub.Domain/Mcp/OnlineSearchTool.cs

@@ -28,8 +28,8 @@ public class OnlineSearchTool : ISingletonDependency
         _baiduApiKey = configuration["BaiduSearch:ApiKey"] ?? "";
     }
 
-    [YiAgentTool("联网搜索"), DisplayName("OnlineSearch"), Description("进行在线搜索，获取最新的网络信息")]
+    [YiAgentTool("联网搜索"), DisplayName("OnlineSearch"), Description("进行在线搜索，获取最新的网络信息，近期信息是7天，实时信息是1天")]
-    public async Task<string> OnlineSearch(string keyword)
+    public async Task<string> OnlineSearch([Description("搜索关键字")]string keyword, [Description("距离现在多久天")]int? daysAgo = null)
     {
         if (string.IsNullOrWhiteSpace(keyword))
         {
@@ -49,6 +49,22 @@ public class OnlineSearchTool : ISingletonDependency
                 }
             };
 
+            // 设置时间范围过滤
+            if (daysAgo.HasValue)
+            {
+                requestBody.SearchFilter = new BaiduSearchFilter
+                {
+                    Range = new BaiduSearchRange
+                    {
+                        PageTime = new BaiduSearchPageTime
+                        {
+                            Gte = $"now-{daysAgo.Value}d/d",
+                            Lte = "now"
+                        }
+                    }
+                };
+            }
+
             var jsonContent = JsonSerializer.Serialize(requestBody, BaiduJsonContext.Default.BaiduSearchRequest);
             var content = new StringContent(jsonContent, Encoding.UTF8, "application/json");
 
@@ -135,6 +151,40 @@ public class BaiduSearchRequest
 {
     [JsonPropertyName("messages")]
     public List<BaiduSearchMessage> Messages { get; set; } = new();
+
+    [JsonPropertyName("search_filter")]
+    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+    public BaiduSearchFilter? SearchFilter { get; set; }
+}
+
+/// <summary>
+/// 百度搜索过滤器
+/// </summary>
+public class BaiduSearchFilter
+{
+    [JsonPropertyName("range")]
+    public BaiduSearchRange? Range { get; set; }
+}
+
+/// <summary>
+/// 百度搜索范围
+/// </summary>
+public class BaiduSearchRange
+{
+    [JsonPropertyName("page_time")]
+    public BaiduSearchPageTime? PageTime { get; set; }
+}
+
+/// <summary>
+/// 百度搜索时间范围
+/// </summary>
+public class BaiduSearchPageTime
+{
+    [JsonPropertyName("gte")]
+    public string? Gte { get; set; }
+
+    [JsonPropertyName("lte")]
+    public string? Lte { get; set; }
 }
 
 /// <summary>
@@ -191,6 +241,9 @@ public class BaiduSearchReference
 
 [JsonSerializable(typeof(BaiduSearchRequest))]
 [JsonSerializable(typeof(BaiduSearchResponse))]
+[JsonSerializable(typeof(BaiduSearchFilter))]
+[JsonSerializable(typeof(BaiduSearchRange))]
+[JsonSerializable(typeof(BaiduSearchPageTime))]
 [JsonSourceGenerationOptions(PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase)]
 internal partial class BaiduJsonContext : JsonSerializerContext
 {